Seasonal affective disorder (SAD) is a form of depression caused by decreased natural light during the winter months. The constant grey, rain, and snow can all contribute to SAD. There's plenty to enjoy about this time of the year for the lucky ones who don't experience this terrible illness. According to Professor Murray, it is quite rare in Australia, where about 1 in 300 is affected by the illness. Still, awareness is key, and it helps to know what one can do to help ease the symptoms.